Tube socket



y 1941. w. w. MATHERN 2,240,658

TUBE SOCKET Filed Ma r-ch. 31, 1958 Ha. fl 1 11;. J.

3 nventor Patented May 6, 1941 UNITE TUBE SOCKET Wiiliam W. Mathern, Maple Shade, N. J assignor to Radio Corporation of America, a corporation of Delaware Application March 31, 1938, Serial No. 199,155

3 Claims.

My invention relates to electric plug and socket connections, and more particularly to sockets for electron discharge devices of the type having terminal pins or prongs extending from the base thereof.

Since the introduction of metal thermionic tubes, a much smaller tube has been available. Moreover, while the dimensions of a metal tube are much smaller than its predecessor, the glass tube, the number of elements within the tube have, in many instances, been increased and, likewise, the number of terminal pins or prongs extending from the base thereof. Thus, a reduction in the diameter and/or length of the terminal pins or prongs was necessary in view of a much smaller tube base and a greater number of pins or prongs extending therefrom.

For the above reasons, analogous tube sockets of the prior art were not altogether satisfactory for use with tubes of the metal type by reason of the fact that such tubes had, among other things, a tendency to work out of the socket. This has been true, especially in applications where the tube is subject to considerable vibration or where the tube is supported in a horizontal or inverted position.

It is, accordingly, an object of my invention to provide a tube socket of the character specified, which will securely retain the terminal prongs of a vacuum tube or the like in operative position.

A further object of my invention is to provide a tube socket, as specified, wherein .each contact member comprises a unitary resilient member.

A still further object of my invention is to provide a tube socket, as specified, which may be produced and assembled at low cost.

A further object of my invention is to provide a tube socket, as specified, wherein the contact members are adapted to establish a five point contact on and about the periphery of the terminal prongs extending from the base of a thermionic tube or the like.

A still further object of my invention is to provide a tube socket, as specified, wherein the contact or prong engaging members are not permanently distended or deformed by reason of frequent insertion and withdrawal of a thermionic tube or the like.

A further object of my invention is to provide a tube socket of the character specified, wherein the contact members are adapted to cooperate with the small prongs of a metal thermionic tube in such a manner that the prongs of the tube are not flexed or sprung out of their normal spacing or alignment.

A still further object of my invention is to provide a tube socket, as specified, wherein the contact or prong engaging members are substantially free to shift relatively to a supporting surface therefor whereby perfect alignment with the prongs of a tube is possible, irrespective of any variation in the spacing of the prongs, upon insertion thereof into the socket.

l A further object of my invention is to provide a tube socket, as specified, wherein the contact and arranged that a plurality of substantially radially disposed edges and/or surfaces exert pressure on and about the periphery of the terminal prong whereby the prong is clutched much after the manner in which a small twist drill is held in a drill chuck.

Other objectes, features and advantages of my invention will appear from the following description taken in connection with the accompanying drawing, in which Figure 1 is a sectional view of a tube socket embodying my invention shown secured to a fragmentary portion of a support therefor and with only two prongs of a vacuum tube in engagement with a like number of contact members for the purpose of clearly illustrating my invention;

Figure 2 is a full bottom plan view of a tube socket embodying my invention minus one contact member for illustration purposes;

Figure 3 is a fragmentary sectional view illustrating a contact member before a terminal prong is associated therewith;

Figure 4 is a similar view illustrating a terminal prong in engagement with a contact member constructed in accordance with my invention;

Figure 5 is a perspective view of a contact member per se;

Figure 6a is an edge view of a pierced blank prior to final formation;

Figure 6b is a plan view of the same;

Figure 7 is a sectional view taken on the line 1-1 of Fig. 4; and.

Figure 8 is an elevational view illustrating the blank, shown in Fig. 6, after the first bending operation.

Referring to Fig. l, a metal type thermionic tube 2 comprising a base 3 having terminal pins or prongs 4 extending therefrom is shown inserted in a tube socket 5, embodying my invention and attached to the underside of a suitable support 5, as by means of rivets I or the like.

The tube socket 5.comprises an upper and lower plate 8 and 9, respectively, formed of fiber or other suitable or preferred insulation material. The upper plate 8 is provided with a central aperture Ill having a key slot ll formed in the edge defining said aperture whereby a centering stem I2, extending centrally from the tube base 3and provided with a longitudinal guide key I3, isadapted for passage therethrough for a purpose Well known to those skilled in theart. Similarly, a plurality of relatively small circumferentially spaced apertures M adapted to register with and to provide passages for the'tube prongs l are also formed in the plateB- concentrically-with the central aperture I0. and radially disposed with respect thereto.

Thelower plate:Q seeured-to-the plate-8-in concentric relation therewith by means of rivets I5 or the like, is provided witha large central opening I6 having its defining edge provided with a plurality of spaced, substantially rectangular notches or slots l-l' so positionedas to be in vertical alignment with the prong apertures M in the plate 8.; A- like number of, spaced, substantially rectangular apertures It" are further provided in theplate 9 in radial alignment with the slotsor notches H but spaced therefrom on a greater radius whereby to provide intervening supporting surfaces [9' therebetween. The'slots l1 and the apertures 18. constitutetwo separate sets of openings, onev of. each set being provided forthe' reception of one of the two substantially. parallel legs or arms ofeach of a plurality of inverted, substantially U-shapedcontact members 2b. with the transverse or base portion 2| of each member supported by one of the intervening surfaces l9, as clearly shown. in Figs. 8 and 4.

Itwill be apparent from an inspection of Figs. 3 and 4 that the contact members 2-8; are not secured to one or the other of the plates Band 9 constituting the base, said members being sandwiched between the joined. base plates and 7 so retainedas to. be substantially free for limited movement within their respective slots relatively to the prong openings l4 formed in the upper base plate 8.

The structure and the method of forming: one of the U-shapedcontact members Zilwillnow be described in connection with a. terminal prong:

4 of a thermionic device 2' shown-in Fig. 1.

In carrying out my-invention, a suitable-blank 22 of spring brass, for example, ispierced. along linear and arcuate paths extendinglongitudinally of the blank, as-indicated' at 23; 24 and 25 in Figs. 6a and 6binsuitable diesprovided for this purpose. Simultaneously withthe piercing of the metal blank 22, the marginal edge portions 26" of the blank 22, opposite each side of: the element 25, are out along arcuate paths extending: short. of: the right hand free end-of I the blank, as viewed in Fig. 6b. During this piercing and. cuttingbperation, the elements 23,1. 24. and. 25; are biased out, of the'plan'e of the. blanln 22: substantially as shown in Fig. 6a. The element 23 constitutes awiring terminal. tab,the element:.2;4-'ta stabilizing toe, and the element 25 a contact tongue, all for a purpose hereinafter set forth.

After the blank 22 has been pierced and out along arcuate and linear paths, respectively, the blank 22 is ready for the first of two bending operations.

Describing now the first bending operation, the right hand end portion R of the blank 22 which is pierced and out along arcuate paths is placed between suitably formed complementary die elements (Fig. 8) to bend the tongue 25 into its final predetermined position and, at the same time, to bend said tongue slightly at a point midwayof its length. Simultaneously therewith, theremaining portions 26 of the blank 22 adjacent to the tongue 25 are bent into a position where they extend across the plane of the tongue .25 to complete the prong engaging leg of the contact member 2|], as will be clearly understood from-an inspection of Figs. 5 and 8.

In. the final bending operation, the opposite endpor-tionL of the blank 22.is placed in another die (not shown) to bend said. opposite endportion substantially at right angles to the intermediate blank portion 2 i, whereby a substantially U-shaped contact member is formed. In this final bending operation, the element 24, which is biasedsubstantially out of the plane of the blank 22, remainsin this position whereby it formsan extension of the intermediate or base portion 2i of the U-shaped contact. member 20 and serves as a stabilizing toe whereby any tendency of each contactmember torockor tilt on its supporting surface l9.v is obviated and the legs thereof are maintained. substantially normal to the base plates 8' and. 9' when a terminal prong 4. is-forced into and out of engagement with eachof said contact members 2B.

The stabilizing toe, indicated at 2.5. (Fig. 5), is slightly biased or cantedupwardly out. of. the plane. of. the intermediate or base portion. 2-]. of the contact member. 2.0 in order to counteract the downward pressure to which. the prong engaging leg of each contact. member may be sub.- jected by the forced entry ofa terminal prong into engagement therewith.

Referring againv to Figures3 and. 4, the cooperable actionv between a terminalprong 4 and a .contactmember Zfli is as follows:

Upon entrance of.a. terminal prong. 4lintov one. of .tlie. prong openings. It, the end ofthe prong first contacts. the. upper portion of the tongue 25. Continued. downward movement. of the prong. 4 causesthe. tongue. to. be deflected. radially out wardly of. the prong. .While the-tongue is being deflected out of itsnormal position, theprong 4 passes the narrowest point. between the bent marginaLportions. 25. When. the prong passes this narrow, point, the marginalportions 26- are sprung slightly. apart. whereby. torsional tension is imparted thereto. Moreover, the tongue 25, contacts the inner transverse edge, of the end portion R and draws inner prong-engaging edges of the bent marginal portions 25 into, firm contact with the prongl' and-aids to maintain the; trapezoidal formationv of the. marginal: portions 25.

Referring to Figure '7 itwill be observed-thatthe marginalportions 26'do not contact'the prong 4i at the point indicated bythe arrow, Thisis due to the cylindrical configuration of the prong 4; whereby the pointsof contact occur at a plurality of diametrically opposite points about its pe= riphery andlengthwise thereofas indicated at 0.

-- The above noted points of contact total four; the

fifth point occurs at t where the intermediate portion of the tongue 25 remains in contact with the prong 4. It will also be observed that the fifth point of contact it occurs on the prong substantially intermediate the spaced, diametrically opposite points of contact 0.

Referring again to Figure 5, it is to be observed that the outwardly concaved marginal edges of the tongue 25 do not contact the outwardly concaved edges of the marginal portions 26 extending across the plane of the tongue 25. This is accomplished by piercing the blank along arcuate paths longitudinally thereof and the bending of the marginal portions 26 so as to extend across the plane of the tongue 25.

It is also to be observed that the smallest distance between the bent marginal portions 26 occurs at the point indicated by the arrow in the above noted figure.

In order to obviate the possibility of electrical leakage between any two contact members 2|] in the socket 5, the outer edge of the marginal portions 26 are also out along arcuate paths whereby sufiicient clearance between the assembled contact members 20, as viewed in Figure 2, is aiforded.

Although I have shown and described certain specific embodiments of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

What I claim is:

l. A contact for receiving a cylindrical prong, said contact comprising a resilient strip having a central tongue, marginal portions extending along the sides of said tongue and a web connecting said marginal portions adjacent the free end of the tongue, said marginal portions being bent intermediate their length to provide angular portions extending across the plane of the tongue and forming with the tongue a prong receiving channel extending lengthwise of the tongue with the web positioned rearwardly of said tongue and providing a stop for said tongue when said prong is inserted in said channel.

2. The invention as set forth in claim 1 and wherein the adjacent edges of said marginal portions diverge in opposite directions from the point at which they are bent.

3. The invention as set forth in claim 1 wherein the tongue portion of said channel is biased in a direction opposite to the direction in which said marginal portions are bent whereby said tongue is maintained in contact with said prong.

WILLIAM W. MATIEERN. 

